1. Field of the Invention
The present invention relates to a refrigerator, and more particularly, to a cold air guide structure of an ice-making chamber of a cold chamber door in which an ice-making unit is installed in an insulation space (Hereinafter, referred to as “ice-making chamber”) provided inside of the cold chamber door, and cold air can be guided to the maximum into the ice-making chamber.
2. Description of the Related Art
Generally, in a refrigerator, cold air is generated by a refrigeration cycle, which is performed by a compressor, a condenser, an expansive valve and an evaporator, to reduce an internal temperature, thereby freezing a food or keeping the food cool.
The refrigerator is classified into a top mount-type refrigerator having a freezing chamber and a cold chamber partitioned up and down, a bottom freezer-type refrigerator having a cold chamber and a freezing chamber partitioned up and down, and a side by side-type refrigerator having a freezing chamber and a cold chamber partitioned left and right.
As shown in FIG. 1, the bottom freezer-type refrigerator has a cold chamber 2 and a freezing chamber 5 partitioned up and down by a barrier 11 of a refrigerator body 1; a cold chamber door 3 for opening and closing the cold chamber 2; and a freezing chamber door 4 for opening and closing the freezing chamber.
The bottom freezer-type refrigerator having a conventional ice-making unit is shown in FIG. 2. Referring to FIG. 2, the refrigerator includes a compressor 6 installed in a machine chamber, which is disposed at a rear of a refrigerator body 1, to compress a refrigerant; an evaporator 7 and a ventilation fan 8 connected with the compressor 6 through a refrigerant pipe to be installed at a rear wall of the freezing chamber to supply cold air; ducts 9 and 10 for returning the cold air; and an ice-making unit 12 installed inside of the freezing chamber door 4 to ice a supplied water, and take out and keep pieces of ice.
The ice-making unit is mainly comprised of an ice maker 20 for icing the supplied water and taking out the pieces of ice; and an ice bank 30 for keeping the pieces of ice taken out by the ice maker 20.
The above-described ice-making unit of the bottom freezer-type refrigerator is described with reference to FIG. 2 as follows.
First, the refrigerant changed into a low-temperature and low-pressure vaporized state by the evaporator 7 is flowed to the compressor 6 and is compressed at a high temperature and a high pressure by the compressor 6, and the compressed refrigerant is cooled and condensed while being passing through the condenser to be changed into a high-pressure liquid state.
The refrigerant changed into the high-pressure liquid state passes through the expansive valve (not shown) while being reduced in pressure to be in a state of facilitating the evaporation of the refrigerant in the evaporator 7 through heat-exchange. After that, the refrigerant is again flowed to the evaporator 7 performing an evaporation process of the refrigerant.
The refrigerant flowed to the evaporator 7 is changed into the low-temperature and low-pressure vaporized state through an endothermic reaction for the absorption of an internal heat from the refrigerator while cooling ambient air, and then is flowed to the compressor 6, thereby performing the refrigeration cycle.
At this time, the air (cold air) emitting a heat while being cooled using the refrigerant through the heat exchange with the evaporator 7 is discharged from a freezing chamber 5 side by driving the ventilation fan 8 installed at an upper side of the evaporator 7. At this time, the refrigerant discharged by the driving of the ventilation fan 8 is respectively branched to the freezing chamber 5 and the cold chamber 2 depending on a damper operation.
Meanwhile, the cold air is supplied to the cold chamber by the cold air discharge port 2b through the cold air supply duct 2a installed at a rear wall of the freezing chamber.
After that, the cold air used in the cold chamber 2 and the freezing chamber 5 is again returned to a lower side of the evaporator through the return ducts 9 and 10.
Here, the cold air discharged to the freezing chamber 5 side is introduced to the ice maker 20 of the ice-making unit 12 installed at the freezing chamber 5, to allow the ice-making unit 12 to perform ice manufacture.
The ice-making unit 121 is in detail described with reference to FIG. 3 in the following. The ice maker 20 includes a mold 21 for making the pieces of ice; and a water supplying unit 22 disposed at one side of the mold 21 to supply water to the mold 21.
The mold 21 is approximately semi-cylindrical shaped, and has a partition rib 21a upwardly protruded at each of predetermined intervals to separate the pieces of ice. Further, a coupling unit 25 is provided at a rear portion of the mold 21 to fix the ice-making unit 12 in the freezing chamber.
A motor unit 23 is installed at one side of the mold 21. A motor is built in the motor unit 23, and an ejector 24 is rotatably connected to a rotary shaft of the motor.
The ejector 24 is installed to allow the rotary shaft to intersect with a center of the mold 21, and a plurality of ejector pins 24a are installed to be approximately vertical to the ejector 24 and be spaced apart at each of predetermined intervals. At this time, the ejector pins 24a are respectively disposed at each of intervals partitioned by the partition rib 21a. 
A plurality of slide bars 26 are extended up to a vicinity of the rotary shaft of the ejector 24 at a rear and upper side of the mold 21.
Further, a heater (not shown) is installed at a bottom surface of the mold 21. The heater heats the surface of the mold for a short time to melt an ice surface adhered to the surface of the mold such that the pieces of ice can be easily separated from the mold 21.
If the ice manufacture is completed in the ice maker 20 through the ice-making reaction, deicing is initiated. That is, in the deicing operation, the ice maker 20 is heated at its lower portion by the heater installed at the bottom surface of the ice maker 20 to be in a state where the pieces of ice can be easily separated. After that, the pieces of ice are separated by the rotation of the ejector 24 rotatably installed at the ice maker 20 to be kept in the ice bank 30 installed at a lower side of the ice maker 20.
Furthermore, an ice-overflow sensing arm 28 is installed at the ice maker 20 to sense an amount of the pieces of ice filled in the ice bank 30. The ice-overflow sensing arm 28 is installed to move up and down, and is also connected to a controller (not shown) built in the motor unit 23. Through the operation of the ice-overflowing arm 28 and the controller, a predetermined amount of the pieces of ice is filled in the ice bank 30. The ice bank 30 keeps the pieces of ice to be consumed.
However, since the ice-making unit is installed in the freezing chamber of the conventional bottom freezer-type refrigerator. The conventional bottom freezer-type refrigerator has a drawback in that a capacity of the freezing chamber is reduced as much as a space occupied by the ice-making unit installed in the cold chamber.